Leading article: Sinn Fein takes a key step towards shared power

The most direct and succinct explanation of the current state of Irish republicanism was this week delivered in a draughty Falls Road monastery by IRA icon Gerry Kelly. Conflicts, he said, ended either with a clear victory or in negotiations, often protracted ones. "It has been accepted by republicans," he declared flatly, "that they cannot push the British out into the sea."

Yesterday's landmark Sinn Fein decision to support the police and justice institutions in Northern Ireland flowed from recognition of that stark fact, as has so much else in the Irish peace process. The idea of formally pledging recognition of the police clearly provided a jolt to the systems of many republicans whose mindsets have been moulded by centuries of Irish rebel tradition.

The decision, convincing though it was, will not therefore go down as a magnificent moment in the annals of republicanism: there are unlikely to be ballads written about the policing debate of '07, with lines such as: "Then up spoke brave McGuinness." Instead, it will be viewed as a difficult but necessary step in the long march of Sinn Fein and the IRA.

Because the goal of political power has displaced that of paramilitary victory, republican guns have been jettisoned. At a certain point they came to be seen as inhibiting rather than advancing the republican cause. Such giant steps as dumping arms and expressing approval of the police would have wrecked many a former revolutionary movement, but Gerry Adams' leadership has managed to hold things together with great skill.

Yesterday's gathering, like the dozen large public meetings that preceded it, heard passionate attacks on the policing system, with considerable anguish expressed by republican grassroots. Yet the cries of pain were not accompanied by alternative plans for advancing "the struggle". (It used to be the "armed struggle": now, significantly and thankfully, it is just "the struggle".)

Those few who dispute Mr Kelly's argument that military victory is impossible are almost universally regarded as anachronistic cranks. The internal achievement of Mr Adams, Mr Kelly and the other leaders has been to drive home the message that politics works. There are few whiffs of defeatism.

Their success in this is most clearly seen in voting patterns in both parts of Ireland. In the north these have established Sinn Fein as the pre-eminent nationalist party, while in the south it has become a potential player in the politics of the Irish Republic, and stands to make gains in this year's general election.

The decision to endorse policing will be warmly welcomed in both Dublin and London as both a milestone in the overall peace process and a crucial tactical step towards power-sharing - as it undoubtedly is. But further progress is unlikely to be rapid.

The very idea of a Paisley-Sinn Fein coalition still causes many minds to boggle. Yet just as Gerry Kelly and company worked out that they could not drive the British into the sea, so too has Ian Paisley come to abandon the dream of somehow crushing republicanism. One of his past election posters pictured him hefting a sledgehammer with the slogan "Smash Sinn Fein". With joint office looming, such talk is no longer heard.

But Paisley, London, Dublin and Washington have been emphatic that power-sharing should not be on offer unless and until republicans spelt out their position on policing. While they will be celebrating yesterday's result, Mr Paisley will probably try to squeeze more from Sinn Fein before he signs on the dotted line for power-sharing. Much more struggling over both policing and politics therefore lies ahead. The crucial difference is that any future struggles will be unarmed.